Question

A Rowland ring of mean radius 15 cm has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of 1.2 A?

Answer 1

given r=15cmr=15cm=0.15m=0.15mN=3500N=3500μr=800μr=800I=1.2AI=1.2AMagnetic field due to the torriod is B=μ0nIB=μ0nI=μ0μr.N2πr=μ0μr.N2πrIISubstituting the valuesB=4×3.14×106−7×800×3500×1.22×3.14×0.15B=4×3.14×106−7×800×3500×1.22×3.14×0.15=4.48T=4.48TAnswer : 4.48T